In the formation of integrated circuits, devices such as transistors are first formed at the surface of a semiconductor substrate, which is a part of a wafer. Interconnect structures are then formed over the semiconductor substrate and the devices. Electrical connectors such as metal bumps and solder balls are formed on the surface of the semiconductor wafer, so that the devices can be accessed. The wafer is then sawed into a plurality of semiconductor dies.
Wafers include scribe lines, which are formed between the semiconductor dies. Scribe lines may be free from circuits, or only include the circuits that can be sawed without affecting the function of the semiconductor dies. For example, monitoring pads may be formed in the scribe lines. To saw the wafer accurately through the scribe lines without damaging the semiconductor dies, the positions of the scribe lines need to be located accurately, and hence the blade used for sawing the wafers may be able to be accurately aligned to the scribe lines.